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88 BASALT FAMILY. Geographic Situation. Europe.—The Bass rock at the mouth of the Frith of Forth, North Berwick Law, Traprain Law, and the Girleton Ilills, all in East Lothian, are principally com posed of clinkstone, and afford many beautiful and highly characteristic varieties of this mineral. It occurs in the island of Arran, isle of Lamlash, and other parts of Scot land, as will be mentioned in the Qeognosy. On the Continent of Europe, it is found in many districts where basalt abounds, as in the Bohemian Mittelgebirge; also in Bavaria, Suabia, Lusatia, Ilessia, France, Italy, Hun gary, &c. • Africa.—Along with basalt, in the island of Teneriffe. America.—Along with trap rocks, both in North and South America. Observations. 1. Charpentier was the person who first directed the particular attention of mineralogists to this substance: in his Mineralogical Description of the Electorate of Sax ony, he gives a very interesting account of it, under the name Hornslate, (Ilornschiefer) Werner afterward* examined it with more minute attention, and introduced it into the oryctognostic system as a distinct species, us- der the name Clinkstone. 2. It is distinguished from Basalt by colour, lustre, fracture, and transparency. 3. It passes on the one hand into Basalt, and on the other into Felspar. 4. Iron-Clay. * Older mineralogists were of opinion, that clinkstone was the same mi neral as that described by Wallerius under the name Corncu.i Jir.ilit: hence they gave it the name Hornslate ; but in this they erred, n* Wallerius’s mi neral appears to he homblende-slate. Born, Ferber, and others, include under their hornsiate, also some varieties of clay-slate, and of mica-slate.
